No terrorist event occurs in a vacuum. When explosives are used, there is a series of planning, procuring, and assembling events that require large quantities of explosives to be transported and deployed. Furthermore, the people transporting and handling explosives become contaminated and emit discernible chemical signatures around them. These invisible plumes could announce to the world that their bearers are up to no good if devices with enough sensitivity are in place to detect the distinct signatures. Once infrequent acts in large cities, acts of terrorism have become more frequent and have now been recorded in more than 160 countries. According to the most recently published Global Terrorism Index by the Institute for Economics and Peace (IEP), 2014 saw the most significant increase in recent history with more than 13,000 terrorist attacks worldwide. Even more alarming is that, in the past decade, more than 50 percent[1] of all acts of terrorism had been carried out against private citizens and the police sworn to protect them. Recent terrorist events in Paris, Belgium, and San Bernardino highlight the importance of improved vigilance to prevent explosions and keep the threat ‘left of boom’.